The Department of Correctional Services announced that 74-year-old Roger Schmidt died minutes before 2 a.m. Wednesday.
Schmidt was serving a 38- to 45-year sentence for first-degree sexual assault of a child. His sentence began on May 18, 2007.
The cause of death has not been determined. Department officials say Schmidt was under treatment for long-term medical conditions.
A grand jury will investigate the death, as happens anytime an inmate dies in the department’s custody.